Image pickup device and electronic apparatus

ABSTRACT

The present technology relates to an image pickup device and an electronic apparatus that are configured to enhance characteristics. A solid-state image pickup device includes a photoelectric conversion section that is arranged on a semiconductor substrate and configured to photoelectrically convert an incident light, a moth-eye section that includes recesses and projections formed on a surface on a light incident side in the semiconductor substrate and has, when a cross section approximately parallel to a direction toward the photoelectric conversion section from the light incident side is viewed, a recessed portion protruding toward the side of the photoelectric conversion section, the recessed portion having a curvature or a polygonal shape, and a region that is arranged adjacent to and opposite to the photoelectric conversion section of the moth-eye section and has a refractive index different from a refractive index of the semiconductor substrate.

TECHNICAL FIELD

The present technology relates to an image pickup device and anelectronic apparatus and, more particularly, to an image pickup deviceand an electronic apparatus that are configured to enhancecharacteristics thereof.

BACKGROUND ART

It is desirable for a solid-state image pickup device to receive lightfrom a subject into a photoreception section without reflection so as tobe converted into an electrical signal by a photoelectric conversionfunction, thereby enhancing the conversion efficiency in thephotoreception section.

For this purpose, it is desired to reduce, as far as possible, thereflection component of light that is caused on each of the interfacesof a laminated structure constituting a solid-state image pickup device.Further, reducing the reflection of light on each interface results inthe reduction of such phenomena caused in the solid-state image pickupdevice as flare, ghost, blooming, and the like.

Therefore, technologies have been proposed in which, in a solid-stateimage pickup device arranged with a photoelectric conversion sectionconfigured to convert received light into electrical charges and asemiconductor substrate including the photoelectric conversion section,a multitude of regions having refractive indexes different from that ofthe semiconductor substrate are arranged between the surface of the sideinto which light enters and the photoelectric conversion section in thesemiconductor substrate, thereby reducing the reflection of incidentlight (refer to PTL 1, for example).

The multitude of the regions having different refractive indexes formedon the semiconductor substrate are formed such that the area of theregions gets larger as the regions get nearer in depth to the surface ofthe side into which light enters in the semiconductor substrate andsmaller as the regions get more remote in depth from this surface.

A moth-eye structure in which the semiconductor substrate is formed in aprojecting (projected) conical manner from the light incident directionto the semiconductor substrate as described above can mitigate thedrastic variation in the refractive index in the interface, one of thecauses of light reflection, thereby reducing the influence of reflectedlight. That is, providing a moth-eye structure allows the refractiveindex to slowly vary along the incident direction of light, therebyreducing the reflection of light.

CITATION LIST Patent Literature [PTL 1]

JP 2015-18906A

SUMMARY Technical Problems

However, the technology is sometimes unable to provide solid-state imagepickup device having sufficient characteristics.

To be more specific, in a case where a region of moth-eye structure isformed on a semiconductor substrate, the influence of the recessed andprojected portions in that region may cause the uneven mold or peelingin an insulation film or a color filter formed on the semiconductorsubstrate. If this happens, noise may be caused on the interface betweenthe insulation film or the color filter and the semiconductor substrate,thereby deteriorating the characteristics such as the sensitivity of thesolid-state image pickup device. In addition, the yield of thesolid-state image pickup device may be lowered.

The present technology has been developed by taking the above-mentionedsituations into consideration so as to enhance the characteristics.

Solution to Problems

In carrying out the present technology and according to one aspectthereof, there is provided an image pickup device. This image pickupdevice includes a photoelectric conversion section that is arranged on asemiconductor substrate and configured to photoelectrically convert anincident light; a moth-eye section that includes recesses andprojections formed on a surface on a light incident side in thesemiconductor substrate and has, when a cross section approximatelyparallel to a direction toward the photoelectric conversion section fromthe light incident side is viewed, a recessed portion protruding towardthe side of the photoelectric conversion section, the recessed portionhaving a curvature or a polygonal shape; and a region that is arrangedadjacent to and opposite to the photoelectric conversion section of themoth-eye section and has a refractive index different from a refractiveindex of the semiconductor substrate.

A projected portion protruding opposite to the photoelectric conversionsection in the moth-eye section may have a curvature or a polygonalshape.

The curvature of the recessed portion may be larger than the curvatureof the projected portion.

The curvature of the recessed portion may be approximately equal to thecurvature of the projected portion.

The refractive index of the semiconductor substrate may be larger thanthe refractive index of the region.

The moth-eye section is formed with a plurality of conical-shapedregions protruding toward the side of the photoelectric conversionsection.

The moth-eye section may be formed with a plurality of conical-shapedregions protruding opposite to the photoelectric conversion section.

The conical-shaped regions may be arranged in lattice.

The plurality of conical-shaped regions including sizes or shapes thatmay be different from each other are irregularly arranged.

The moth-eye section may be formed with the plurality of the recessedportions that are linear in shape long along the direction approximatelyperpendicular to the cross section and arranged side by side.

Between the photoelectric conversion sections mutually adjacent to eachother in the semiconductor substrate, an inter-pixel separation sectionconfigured to electrically separate the photoelectric conversionsections from each other may be arranged.

An inter-pixel light blocking film for blocking the light may be formedinside the inter-pixel separation section.

In the image pickup device according to the first aspect of the presenttechnology, there are provided a photoelectric conversion section thatis arranged on a semiconductor substrate and configured tophotoelectrically convert an incident light; a moth-eye section thatincludes recesses and projections formed on a surface on a lightincident side in the semiconductor substrate and has, when a crosssection approximately parallel to a direction toward the photoelectricconversion section from the light incident side is viewed, a recessedportion protruding toward the side of the photoelectric conversionsection, the recessed portion having a curvature or a polygonal shape;and a region that is arranged adjacent to and opposite to thephotoelectric conversion section of the moth-eye section and has arefractive index different from a refractive index of the semiconductorsubstrate.

In carrying out the present technology and according to a second aspectthereof, there is provided an electronic apparatus. This electronicapparatus includes a photoelectric conversion section that is arrangedon a semiconductor substrate and configured to photoelectrically convertan incident light; a moth-eye section that includes recesses andprojections formed on a surface on a light incident side in thesemiconductor substrate and has, when a cross section approximatelyparallel to a direction toward the photoelectric conversion section fromthe light incident side is viewed, a recessed portion protruding towardthe side of the photoelectric conversion section, the recessed portionhaving a curvature or a polygonal shape; and a region that is arrangedadjacent to and opposite to the photoelectric conversion section of themoth-eye section and has a refractive index different from a refractiveindex of the semiconductor substrate.

In the electronic apparatus according to the second aspect of thepresent technology, there are provided a photoelectric conversionsection that is arranged on a semiconductor substrate and configured tophotoelectrically convert an incident light; a moth-eye section thatincludes recesses and projections formed on a surface on a lightincident side in the semiconductor substrate and has, when a crosssection approximately parallel to a direction toward the photoelectricconversion section from the light incident side is viewed, a recessedportion protruding toward the side of the photoelectric conversionsection, the recessed portion having a curvature or a polygonal shape;and a region that is arranged adjacent to and opposite to thephotoelectric conversion section of the moth-eye section and has arefractive index different from a refractive index of the semiconductorsubstrate.

Advantageous Effect of Invention

According to the first aspect and the second aspect of the presenttechnology, the characteristics can be enhanced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram for describing a general moth-eye structure.

FIG. 2 is a diagram illustrating an example of a configuration of animage pickup apparatus to which the present technology is applied.

FIG. 3 is a diagram illustrating an example of a configuration of asolid-state image pickup device.

FIG. 4 is a diagram illustrating an example of a configuration of apixel array section.

FIG. 5 is a diagram illustrating an example of a configuration of amoth-eye section.

FIG. 6 is a diagram illustrating another example of a configuration of amoth-eye section.

FIG. 7 is a diagram illustrating another example of a configuration of apixel array section.

FIG. 8 is a diagram illustrating still another example of aconfiguration of a moth-eye section.

FIG. 9 is a diagram illustrating yet another example of a configurationof a moth-eye section.

FIG. 10 is a diagram illustrating another example of a configuration ofa moth-eye section.

FIG. 11 is a diagram illustrating still another example of aconfiguration of a pixel array section.

FIG. 12 is a diagram illustrating yet another example of a configurationof a pixel array section.

FIG. 13 is a diagram illustrating another example of a configuration ofa pixel array section.

FIG. 14 is a diagram illustrating another example of a configuration ofa pixel array section.

FIG. 15 is a diagram illustrating an example of use in which thesolid-state image pickup device is used.

DESCRIPTION OF EMBODIMENTS

The following describes embodiments to which the present technology isapplied with reference to drawings.

First Embodiment <Moth-Eye Structure>

Firstly, a solid-state image pickup device having a general moth-eyestructure is described.

With a solid-state image pickup device having a general moth-eyestructure, a multilayer wiring layer 12 and a semiconductor substrate 13are laminated on a support substrate 11 as illustrated in FIG. 1.

For example, pixel transistors and wirings are arranged on themultilayer wiring layer 12. In addition, a photo diode 14 is arrangedfor each pixel in the semiconductor substrate 13 and, at the same time,a moth-eye section 15 that is a moth-eye structure region is alsoarranged on a surface portion of the upper side of the semiconductorsubstrate 13 in the drawing.

In the drawing, a color filter 17 and an on-chip lens 18 are arrangedfor each pixel on the upper side of the moth-eye section 15 through aninsulation film 16. It should be noted that, to be precise, aplanarization film is also formed on the portion of the insulation film16.

Further, on the layer on which the insulation film 16 is formed, aninter-pixel light blocking section 19 is also arranged between pixels.The inter-pixel light blocking section 19 prevents the light thatentered the on-chip lens 18 of a predetermined pixel from entering thephoto diode 14 of another pixel.

The solid-state image pickup device having the moth-eye section 15described above can reduce the reflection of the light entering from themoth-eye section 15 into the photo diode 14.

However, with the moth-eye section 15 that is conical in shape asdescribed above, the recessed portion of the photo diode 14 side,namely, the portion indicated with an arrow A11, and the projectedportion of the insulation film 16 side, namely, the portion indicatedwith an arrow A12, are not planar but are sharp in shape. Therefore,forming the insulation film 16 on the surface of the moth-eye section 15and then forming the color filter 17 on that surface easily cause unevenmold or peeling of the insulation film 16 or the color filter 17. Thatis, this deteriorates the adhesion.

Consequently, noise is caused on the interface and so on between thesemiconductor substrate 13 and the insulation film 16, therebydeteriorating the characteristics (performance) such as the sensitivityor lowering the yield.

Therefore, with the present technology, in a moth-eye structure in whichthe semiconductor substrate is formed in a projecting or recessing conesor polygonal pyramids manner from the light incident side to thesemiconductor substrate, the recessed portion of the semiconductorsubstrate is provided with a curvature, thereby preventing the unevenmold and peeling of the insulation film, the color filter, and so onthat are formed on the semiconductor substrate so as to enhance theadhesion.

The structure described above allows the prevention of the occurrence ofnoise in the proximity of the interface between an insulation film, acolor filter, and so on, and a semiconductor substrate, therebyrealizing the enhancement of the sensitivity of solid-state image pickupdevice and the prevention of ghosts and so on due to reflected lightand, at the same time, enhance the yield.

<Exemplary Configuration of Image Pickup Apparatus>

The following describes specific embodiments to which the presenttechnology is applied.

The present technology is applicable to various kinds of electronicapparatuses having a solid-state image pickup device, such as digitalcameras, video cameras, mobile telephones, copy machines, and so on aswell as the solid-state image pickup device; in what follows, however,the description will be done by use of an example in which the presenttechnology is applied to an image pickup apparatus having a solid-stateimage pickup device.

FIG. 2 is a diagram illustrating an example of a configuration of animage pickup apparatus to which the present technology is applied.

An image pickup apparatus 41 illustrated in FIG. 2 has an optical system51 including a lens group and so on, a solid-state image pickup device52, a DSP (Digital Signal Processor) circuit 53, a frame memory 54, adisplay section 55, a recording section 56, a manipulation section 57,and a power supply section 58. Further, the DSP circuit 53 through thepower supply section 58 are interconnected via a bus line 59.

The optical system 51 captures an incident light (an image light) comingfrom a subject so as to form an image on the image pickup surface of thesolid-state image pickup device 52. The solid-state image pickup device52 converts the light quantity of the incident light formed on the imagepickup surface by the optical system 51 into an electrical signal thatis outputted as a pixel signal.

The DSP circuit 53 processes the signal coming from the solid-stateimage pickup device 52. For example, the DSP circuit 53 processes thesignal coming from each pixel obtained by an image pickup operation bythe solid-state image pickup device 52, thereby processing of expandingthe processed signal into the frame memory 54.

The display section 55, including a liquid crystal display panel or anorganic EL (Electro Luminescence) panel, displays a moving image or astill image taken by the solid-state image pickup device 52. Therecording section 56 records the moving image or the still image takenby the solid-state image pickup device 52 to a recording medium such asa DVD (Digital Versatile Disk) or the like.

The manipulation section 57, operated by a user, issues manipulationcommands with respect to various functions provided by the image pickupapparatus 41. The power supply section 58 supplies powers for operation,from time to time, to the targets of power supply, namely, the DSPcircuit 53, the frame memory 54, the display section 55, the recordingsection 56, and the manipulation section 57.

<Exemplary Configuration of Solid-State Image Pickup Device>

Further, the solid-state image pickup device 52 illustrated in the FIG.2 is configured as illustrated in FIG. 3, for example.

The solid-state image pickup device 52 is a solid-state image pickupapparatus such as a CMOS (Complementary Metal Oxide Semiconductor) imagesensor or the like.

The solid-state image pickup device 52 has a pixel array section 81obtained by forming an on-chip lens or the like on a semiconductorsubstrate (chip) not illustrated and a peripheral circuit section onwhich integrated on the same semiconductor substrate on which the pixelarray section 81 is formed. The peripheral circuit section has avertical drive section 82, a column processing section 83, a horizontaldrive section 84, and a system control section 85.

Additionally, the solid-state image pickup device 52 has a signalprocessing section 88 and a data storage section 89. It should be notedthat the signal processing section 88 and the data storage section 89may be installed on the same substrate on which the solid-state imagepickup device 52 is installed or on a substrate separate from thesubstrate on which the solid-state image pickup device 52 is installed.

The pixel array section 81 has a configuration in which unit pixels(hereafter sometimes referred to simply as pixels) each having aphotoelectric conversion section for generating electrical charges inaccordance with the quantity of received light and storing the generatedelectrical charges are two-dimensionally arranged in a row direction anda column direction, namely, in matrix.

Here, the row direction is an arrangement direction of pixels on rows(namely, the horizontal direction) and the column direction is anarrangement direction of pixels on columns (namely, the verticaldirection). The row direction is the lateral direction in the drawingand the column direction is the up and down direction in the drawing.

In the pixel array section 81, relative to a pixel arrangement ofmatrix, a pixel drive line 86 is wired along the row direction for eachpixel row and a vertical signal line 87 is wired along the columndirection for each pixel column. The pixel drive line 86 transmits adrive signal for driving the reading of a signal from a pixel. It shouldbe noted that, in FIG. 3, one pixel drive line 86 is illustrated as onewiring; however, the number of pixel drive lines 86 is not limited toone. One end of the pixel drive line 86 is connected to an outputterminal corresponding to each row of the vertical drive section 82.

The vertical drive section 82, including a shift register, an addressdecoder, and so on, drives each pixel of the pixel array section 81 allat once, in units of rows, or the like. That is, together with thesystem control section 85 for controlling the vertical drive section 82,the vertical drive section 82 constitutes a drive section that drivesthe operation of each pixel of the pixel array section 81. Although thedrawing of a specific configuration is omitted, this vertical drivesection 82 generally has two scan systems, a read scan system and asweep scan system.

A signal outputted from each unit pixel of a pixel row selectivelyscanned by the vertical drive section 82 is inputted in the columnprocessing section 83 through the vertical signal line 87 for each pixelcolumn. The column processing section 83 executes predetermined signalprocessing on a signal outputted through the vertical signal line 87from each pixel of a selected row for each pixel row of the pixel arraysection 81 and, at the same time, temporarily holds the signal-processedpixel signals.

To be more specific, the column processing section 83 executes noiseelimination processing, DDS (Double Data Sampling), CDS (CorrelatedDouble Sampling), and other sampling processing, AD (Analog Digital)conversion processing, and so on as the signal processing.

The horizontal drive section 84, including a shift register, an addressdecoder, and so on, sequentially selects a unit circuit corresponding toa pixel column of the column processing section 83. This selective scanby the horizontal drive section 84 sequentially outputs the pixelsignals signal-processed for each unit circuit in the column processingsection 83.

The system control section 85, including a timing generator forgenerating various types of timing signals and so on, executes drivecontrol on the vertical drive section 82, the column processing section83, and the horizontal drive section 84 on the basis of various types oftimings generated by that timing generator.

The signal processing section 88 at least has a computation processingfunction and executes various types of signal processing operations suchas computation processing on the pixel signals outputted from the columnprocessing section 83. The data storage section 89 temporarily storesthe data necessary for the signal processing to be executed in thesignal processing section 88.

<Exemplary Configuration of Pixel Array Section>

In addition, pixels each including a photodiode and so on are arrangedon the pixel array section 81, the cross section of this pixel arraysection 81 being configured as illustrated in FIG. 4, for example.

In the example illustrated in FIG. 4, the pixel array section 81 has asemiconductor substrate 121, a multilayer wiring layer 122 formed on asurface of the semiconductor substrate 121, and a support substrate 123.

The semiconductor substrate 121 is constituted of silicon, for example,and the thickness of the semiconductor substrate 121 is 1 to 6 μm, forexample.

Further, in the semiconductor substrate 121, a photodiode 124 is formedon a pixel basis by forming a semiconductor region of N-type (the secondconductivity) for each pixel in a semiconductor region of P-type (thefirst conductivity), for example. This photodiode 124 is a photoelectricconversion section for receiving the incident light from the outside tophotoelectrically convers the received light, thereby storing theresultant electrical charges. It should be noted that, in FIG. 4, onlyone of the multiple photodiodes 124 is assigned with a reference sign.

In the drawing of the N-type semiconductor region providing anelectrical charge storage region of the photodiode 124, the interface ofthe P-type semiconductor region (the interface on the side ofphotoreception) of the upper side constitutes a moth-eye section 125that functions as a reflection prevention section for preventing thereflection of incident light through a so-called moth-eye structure inwhich a microscopic recessed and projected structure is formed.

That is, microscopic recesses and projections are formed on the surfaceof the side in which the light from the outside enters in thesemiconductor substrate 121, this recessed and projected portionproviding the moth-eye section 125.

The microscopic recessed and projected portion of the moth-eye section125 are formed conical, such as polygonal pyramids or cones. Also, inthis microscopic recessed and projected structure, a region in which thesemiconductor substrate 121 is recessed has a curvature (no angle) whenviewing the cross section in the direction toward the photodiode 124 inthe semiconductor substrate 121, namely, approximately parallel to thedownward direction from the light incident side.

In this example, a portion indicated by arrow A21 of the moth-eyesection 125, for example, has a curvature that is a recessed regionprotruding downward in the drawing, namely, to the side of thephotodiode 124; in what follows, this recessed region is especiallyreferred to as the recessed portion of the moth-eye section 125.

Further, the microscopic recessed and projected structure of themoth-eye section 125 has a region in which the semiconductor substrate121 is projected when viewing the cross section approximately parallelto the direction toward the photodiode 124 inside the semiconductorsubstrate 121 from the light incident side. In this example, the portionindicated by arrow A22 of the moth-eye section 125, for example, is aregion that is projected upward in the drawing, namely, producing to theside opposite to the photodiode 124; in what follows, especially thisprojected region is referred to also as the projected portion of themoth-eye section 125.

The moth-eye section 125 may have a shape in which not only the recessedportion but also the projected portion has a curvature; however, it hasbeen confirmed by the applicants hereof that especially a largecurvature of the recessed portion is effective in enhancing thecharacteristics (the performance) of the solid-state image pickup device52.

Consequently, with the moth-eye section 125, the curvature of a recessedportion may be handled to be approximately equal to the curvature of aprojected portion; however, in this example, each recessed portion andeach projected portion are formed such that the curvature of therecessed portion is larger than the curvature of the projected portion.

To be more specific, in a case where visible light is detected with thephotodiode 124, let the curvature radius of a recessed portion be RA andthe curvature radius of a projected portion be RB, then it has beenconfirmed that it is especially effective in the enhancement of thecharacteristics if RA/RB 1.3 is satisfied. Hence, with the moth-eyesection 125, the projected portions and the recessed portions are formedto as to satisfy this relation.

It should be noted that the moth-eye section 125 having the recessedportions and the projected portions such as above is formed by use ofthe anisotropy of wet etching. Further, also in embodiments andvariations to be described later, the projected portion and the recessedportion of the moth-eye section 125 may satisfy RA/RB≥1.3 or haveapproximately the same curvature between the recessed portion and theprojected portion.

For example, with the moth-eye section 125, a conical pitch (length)equivalent to a cycle in which the microscopic recesses and projectionsincluding recessed portions and projected portions are horizontallyarranged in the drawing is the length that is determined by thewavelength and so on of a light received at the photodiode 124. As oneexample, in a case where a visible light is detected with the photodiode124, for example, the conical pitch of the moth-eye section 125 is setto a range of 40 to 380 nm.

The conical pitch and the recessed and projected depth, and thecurvature radius of recessed portion and projected portion of themoth-eye section 125 may be properly determined in accordance with thewavelengths of such lights to be detected by the photodiode 124 asvisible light, infrared light, and lights of other wavelength bands.

The multilayer wiring layer 122 has two or more wiring layers andinter-layer insulation films. Further, the multilayer wiring layer 122is formed with two or more pixel transistors 126 for reading electricalcharges stored in the photodiode 124 and a wiring 127 connected tovarious types of the pixel transistors 126 and so on. For example, thewiring 127 is a wiring such as the vertical signal line 87 illustratedin FIG. 3.

Further, the light incident side of the semiconductor substrate 121,namely, the surface opposite to the photodiode 124 side in the moth-eyesection 125 of the semiconductor substrate 121 is formed with aninsulation film 128 and an inter-pixel light blocking film 129. Inaddition, a color filter layer 130 is formed on the upper side in thedrawing of the region in which the insulation film 128 and theinter-pixel light blocking film 129 are formed.

It should be noted that, to be more precise, a planarization film, notillustrated, is formed between the insulation film 128 and theinter-pixel light blocking film 129 and the color filter layer 130.Further, instead of the insulation film 128, a transparent insulationfilm may be formed and this transparent insulation film may be formed bycombining and laminating two or more materials.

Here, the refractive index of the insulation film 128 arranged adjacentto the moth-eye section 125 is made different from the refractive indexof the semiconductor substrate 121 constituting the moth-eye section125, especially the P-type semiconductor region.

To be more specific, let the refractive index of the insulation film 128arranged adjacent to the moth-eye section 125 be n1 and the refractiveindex of the semiconductor substrate 121 constituting the moth-eyesection 125 be n2, then refractive index n1 and refractive index n2satisfy a relation refractive index n1<refractive index n2, for example.

Thus, making refractive index n2 of the semiconductor substrate 121 belarger than refractive index n1 of the insulation film 128 allows thelight reflection blocking effect provided by the moth-eye section 125 tobe further enhanced.

The inter-pixel light blocking film 129 is formed at a position betweenpixels on the side of the moth-eye section 125 of the semiconductorsubstrate 121 so as to function as an inter-pixel light blocking sectionfor separating the pixels.

The color filter layer 130 is arranged with a color filter 131 thattransmits only a predetermined color component for each pixel, namely,for each photodiode 124. For example, in the color filter layer 130, thefilters of the three colors R (Red), G (Green), and B (Blue) arearranged, in Bayer array, as the color filters 131 for the pixels.

These color filters 131 are formed by rotationally coating thephotosensitive resin containing a color element such as pigment or dye.

It should be noted that the arrangement of the color filters 131 may notonly Bayer array but also any one of other arrangements or the filtersof other colors, W (White), Y (Yellow), and so on, may be arranged asthe color filters 131.

Further, the upper side of each color filter 131 in the drawing, namely,the light incident side thereof, is formed with an on-chip lens 132 foreach pixel. In the on-chip lens 132, the light entered from the outsideis condensed to be efficiently put into the photodiode 124 through thecolor filter 131.

In the pixel array section 81 configured as described above, the lightfrom a subject enters the on-chip lens 132 from the upside in thedrawing. Next, the light from the subject is condensed by the on-chiplens 132 to be put in the photodiode 124 through the color filter 131,the insulation film 128, the moth-eye section 125, and the P-typesemiconductor region of the semiconductor substrate 121.

At this moment, of the light condensed by the on-chip lens 132 of apredetermined pixel, the light traveling toward a pixel adjacent to thepredetermined pixel is blocked by the inter-pixel light blocking film129, so that this light is prevented from entering the photodiode 124 ofanother pixel.

The photodiode 124 photoelectrically converts the light entered from asubject so as to store the electrical charges obtained as a result ofthe conversion. Then, a voltage signal corresponding to the electricalcharges stored in the photodiode 124 is read to the column processingsection 83 through the pixel transistor 126 and the vertical signal line87 that is the wiring 127.

In the image pickup apparatus 41 described above, providing a curvatureto the recessed portion of the moth-eye section 125 so as to provide acomparatively gentle shape to the surface of the moth-eye section 125,thereby allowing the prevention of the occurrence of the uneven mold orpeeling of the insulation film 128 or the color filter 131 that areformed on the semiconductor substrate 121. That is, this setup allowsthe enhancement of the adhesion between the semiconductor substrate 121and the insulation film 128 or the color filter 131.

Consequently, the noise near the interface (boundary surface) of theinsulation film 128 and the color filter 131 can be prevented fromoccurring, thereby enhancing the performance (characteristics) of thesolid-state image pickup device 52, such as the enhancement in thesensitivity of the solid-state image pickup device 52 and the preventionof the occurrence of ghost and the like due to reflected light. Inaddition, the yield of the solid-state image pickup device 52 can alsobe enhanced.

The following describes one example of the materials constituting eachsection of the pixel array section 81 illustrated in FIG. 4.

The insulation film 128 arranged in the upper side in FIG. 4, namely,the light incident side of the moth-eye section 125, is formed, forexample, by silicon oxide (SiO₂), silicon nitride (SiN), siliconoxynitride (SiON), hafnium oxide (HfO₂), aluminum oxide (Al₂O₃),zirconium oxide (ZrO₂), tantalum oxide (Ta₂O₅), titanium oxide (TiO₂),lanthanum oxide (La₂O₃), praseodymium oxide (Pr₂O₃), cerium oxide(CeO₂), neodymium oxide (Nd₂O₃), promethium oxide (Pm₂O₃), samariumoxide (Sm₂O₃), europium oxide (Eu₂O₃), gadolinium oxide (Gd₂O₃), terbiumoxide (Tb₂O₃), dysprosium oxide (Dy₂O₃), holmium oxide (Ho₂O₃), thuliumoxide (Tm₂O₃), ytterbium oxide (Yb₂O₃), lutetium oxide (Lu₂O₃), yttriumoxide (Y₂O₃), or resin. In addition, some of these materials may becombined and laminated to form the insulation film 128.

In addition, in a case where a transparent insulation film is usedinstead of the insulation film 128, making the refractive index of thetransparent insulation film larger than the refractive index of thesemiconductor substrate 121 as with the case of the insulation film 128can further enhance the light reflection blocking effect caused by themoth-eye section 125.

Further, the transparent insulation film can be formed, for example, bysilicon oxide (SiO₂), silicon nitride (SiN), silicon oxynitride (SiON),hafnium oxide (HfO₂), aluminum oxide (Al₂O₃), zirconium oxide (ZrO₂),tantalum oxide (Ta₂O₅), titanium oxide (TiO₂), lanthanum oxide (La₂O₃),praseodymium oxide (Pr₂O₃), cerium oxide (CeO₂), neodymium oxide(Nd₂O₃), promethium oxide (Pm₂O₃), samarium oxide (Sm₂O₃), europiumoxide (Eu₂O₃), gadolinium oxide (Gd₂O₃), terbium oxide (Tb₂O₃),dysprosium oxide (Dy₂O₃), holmium oxide (Ho₂O₃), thulium oxide (Tm₂O₃),ytterbium oxide (Yb₂O₃), lutetium oxide (Lu₂O₃), yttrium oxide (Y₂O₃),or resin. In addition, some of these materials may be combined andlaminated to form the transparent insulation film.

In addition, a planarization film that is formed together with theinsulation film 128 may be formed with an organic material like resin oran insulation film such as silicon oxide (SiO₂), for example.

In addition, the inter-pixel light blocking film 129 is formed with aresin-based material such as tungsten (W), aluminum (Al), or copper (Cu)and the on-chip lens 132 formed with styrene resin, acrylic resin,styrene/acrylic copolymer resin, or siloxane resin.

The semiconductor substrate 121, constituted of silicon, amorphoussilicon, SiC, or the like, is not limited to single crystal silicon and,therefore, may be constituted of any of semiconductor materials that areapplicable as the material of the semiconductor substrate 121constituting the solid-state image pickup device 52.

Further, the moth-eye section 125 illustrated in FIG. 4 has aconfiguration in which plural quadrangular pyramid regions that haveapexes on the lower side in FIG. 4 formed by microscopic recesses andprojections, namely, on the side of the semiconductor substrate 121, andare approximately equal in shape and size with each other, are regularly(lattice-like) arranged, for example, when viewed in the row directionor the column direction of the pixel array section 81.

In such a case, the moth-eye section 125 of the semiconductor substrate121 is as illustrated in FIG. 5, for example. It should be noted thatFIG. 5 is a perspective view of the moth-eye section 125 and, in FIG. 5,the same reference signs are assigned to the portions corresponding tothose illustrated in FIG. 4, the description thereof being skipped.

In the example illustrated in FIG. 5, the upper side, in the drawing, ofthe semiconductor substrate 121 is the light incident side, namely, theside of the on-chip lens 132.

For example, as indicated with arrow Q11, the moth-eye section 125 isformed on the surface of the light incident side in the semiconductorsubstrate 121. Then, this moth-eye section 125 has an inverted pyramidstructure in which plural regions of quadrangular pyramid shape havingthe apexes on the lower side in the drawing, namely, on the side of thephotodiode 124 are regularly arranged. Here, the bottom surface of eachquadrangular pyramid is square in shape and the semiconductor substrate121 is engraved and formed such that each region of quadrangular pyramidshape protrudes to the side of the photodiode 124.

Especially, in the moth-eye section 125, the apex portion on the side ofthe photodiode 124 of each quadrangular pyramid region, the portionindicated with arrow W11, for example, is a recessed portion asdescribed above, this recessed portion having a curvature and thereforepresenting a round shape.

Further, some curvature may be given to the hypotenuse portion of eachquadrangular pyramid region of the moth-eye section 125, namely, thehatched portion in the moth-eye section 125 indicated with arrow Q12.Giving a curvature also to the hatched portion described above allowsthe further enhancement in the effect of preventing the uneven mold orpeeling of the insulation film 128 or the color filter 131.

Second Embodiment <Another Exemplary Configuration of Moth-Eye Section>

Meanwhile, in the embodiment described above, the moth-eye section 125is structured such that the recessed portion has a curvature asindicated by arrow Q21 in FIG. 6, for example. However, the recessedportion may have a polygonal shape as indicated by arrow Q22, forexample. It should be noted that, with reference to FIG. 6, the samereference signs are assigned to the portions corresponding to thoseillustrated in FIG. 4, the description thereof being skipped.

FIG. 6 is a diagram illustrating a cross section of the on-chip lens 132approximately parallel to the optical axis in the moth-eye section 125,namely, a cross section approximately parallel to the direction towardthe photodiode 124 from the light incident side of the semiconductorsubstrate 121.

The moth-eye section 125 indicated by arrow Q21 is a partial expansionof the moth-eye section 125 illustrated in FIG. 4 and the portionindicated by arrow W21 in the moth-eye section 125 is recessed, forexample. In this example, since the recessed portion has a curvature,the recessed portion has a gentle curved surface.

By contrast, in the example indicated by arrow Q22, the recessed portionof the moth-eye section 125, the portion indicated by arrow W22, forexample, has a polygonal shape when viewing the cross sectionapproximately parallel to the direction toward the photodiode 124 fromthe light incident side of the semiconductor substrate 121. In thisexample, since the recessed portion is polygonal, a part of a polygon tobe more precise, the recessed portion is approximately curved while therecessed portion is formed with multitude of angles.

As described above, providing a structure in which the cross section ofthe recessed portion has multiple angles makes the shape of the recessedportion indicated by arrow W22 smoother overall than the recessedportion of the moth-eye section 15 illustrated in FIG. 1, for example,thereby preventing the uneven mold or peeling of the insulation film 128and the color filter 131 that are formed on the semiconductor substrate121. Especially, in this example, fine angles are provided on therecessed portion, so that the film peeling prevention effect of theinsulation film 128 can be further enhanced.

It should be noted that, in the example indicated by arrow Q22, themoth-eye section 125 also has a structure in which multiple recessedportions that are polygonal and have approximately equal sizes asindicted by arrow W22 are arranged in lattice, namely, in matrix andregularly. Also, not only the recessed portions but also projectedportions may be formed with cross section of each projected portionshaped in a polygonal manner.

Third Embodiment <Another Exemplary Configuration of Pixel ArraySection>

It is also practicable to form a reflection blocking film between themoth-eye section 125 and the insulation film or the transparentinsulation film. In such a case, the pixel array section 81 has astructure as illustrated in FIG. 7, for example. It should be noted thatwith reference to FIG. 7, the same reference signs are assigned to theportions corresponding to those illustrated in FIG. 4, the descriptionthereof being appropriately skipped.

In the example illustrated in FIG. 7, the surface portion of the on-chiplens 132 in the moth-eye section 125 is formed with a reflectionblocking film 161 and the surface of this reflection blocking film 161is further formed with a transparent insulation film 162 and aplanarization film 163. Further, the color filter layer 130 is formed onthe upper side in the drawing of the planarization film 163 and theinter-pixel light blocking film 129.

Thus, forming the reflection blocking film 161 on the surface of themoth-eye section 125 can further enhance light reflection blockingeffects.

It should be noted that, also in this example, the microscopic recessedand projected portions of the moth-eye section 125 have inverted pyramidstructure like the example illustrated in FIG. 4. That is, the moth-eyesection 125 has a structure in which plural quadrangular pyramid regionsof the approximately same shape and the approximately same size havingapexes on the side of the photodiode 124 are arranged in lattice andregularly, the apex portion of the side of the photodiode 124 in eachquadrangular pyramid region providing a recessed portion having acurvature.

Further, the reflection blocking film 161 is formed, for example, bysilicon nitride (SiN), hafnium oxide (HfO₂), aluminum oxide (Al₂O₃),zirconium oxide (ZrO₂), tantalum oxide (Ta₂Ta₅), titanium oxide (TiO₂),lanthanum oxide (La₂O₃), praseodymium oxide (Pr₂O₃), cerium oxide(CeO₂), neodymium oxide (Nd₂O₃), promethium oxide (Pm₂O₃), samariumoxide (Sm₂O₃), europium oxide (Eu₂O₃), gadolinium oxide (Gd₂O₃), terbiumoxide (Tb₂O₃), dysprosium oxide (Dy₂O₃), holmium oxide (Ho₂O₃), thuliumoxide (Tm₂O₃), ytterbium oxide (Yb₂O₃), lutetium oxide (Lu₂O₃), yttriumoxide (Y₂O₃), or the like. It should be noted that the reflectionblocking film 161 may be formed by combining and laminating some ofthese materials. Further, if the refractive index of the reflectionblocking film 161 is also made less than the refractive index of thesemiconductor substrate 121, the light reflection blocking effects canbe further enhanced.

Further, the relation in refractive index between the material of thetransparent insulation film 162 and the semiconductor substrate 121 issimilar to that described with reference to the first embodiment. Stillfurther, an insulation film may be arranged between the surface of themoth-eye section 125 and the reflection blocking film 161 in theconfiguration illustrated in FIG. 7.

Fourth Embodiment <Another Exemplary Configuration of Moth-Eye Section>

With reference to the first embodiment, the example in which themoth-eye section 125 has an inverted pyramid structure includingquadrangular pyramid regions having the apexes on the side of thephotodiode 124; it is also practicable for the moth-eye section 125 tohave a normal pyramid structure as illustrated in FIG. 8, for example.It should be noted that with reference to FIG. 8, the same referencesigns are assigned to the portions corresponding to those illustrated inFIG. 4, the description thereof being appropriately skipped.

In the example illustrated in FIG. 8, the upper side of thesemiconductor substrate 121 in the drawing is the light incident side,namely, the side of the on-chip lens 132.

For example, as indicated by arrow Q31, the moth-eye section 125 isformed on the surface of the light incident side in the semiconductorsubstrate 121. Further, the moth-eye section 125 has an inverted pyramidstructure in which plural quadrangular pyramid regions having the apexeson the side of the on-chip lens 132 that is the light incident side arearranged regularly, namely, in lattice.

Also in this example, each of the plural quadrangular regions isapproximately the same in shape and approximately the same in size witheach other, the bottom surface of each quadrangular pyramid being squarein shape. Further, the semiconductor substrate 121 is engraved to formthese quadrangular pyramid regions such that each quadrangular pyramidregion protrudes toward the side opposite to the side of the photodiode124.

Especially, in the moth-eye section 125, the bottom portion on the sideof each quadrangular pyramid photodiode 124, the portion indicated byarrow W31, for example, is the recessed portion described above. Then,as with the example illustrated in FIG. 5, this recessed portion has around shape having a curvature at the portion protruding toward the sideof the photodiode 124 when viewing the cross section approximatelyparallel to the direction toward the photodiode 124 from the lightincident side of the semiconductor substrate 121.

Therefore, as indicated by arrow Q32, for example, the portion includingthe bottom side of each quadrangular pyramid protruding upward in thedrawing in the moth-eye section 125, namely, the hatched portion, isformed to have a curvature. As with the example illustrated in FIG. 5,this setup allows the prevention of the uneven mold or peeling of theinsulation film 128 or the color filter 131 from on the semiconductorsubstrate 121.

Fifth Embodiment <Still Another Exemplary Configuration of Moth-EyeSection>

Further, as illustrated in FIG. 9, for example, the bottom surface ofthe microscopic recessed and projected portions constituting themoth-eye section 125 may be made rectangular. It should be noted thatwith reference to FIG. 9, the same reference signs are assigned to theportions corresponding to those illustrated in FIG. 4, the descriptionthereof being appropriately skipped.

In this example, the upper side in the drawing of the semiconductorsubstrate 121 is the light incident side, namely, the side of theon-chip lens 132.

The moth-eye section 125 is formed on the surface of the light incidentside in the semiconductor substrate 121 and this moth-eye section 125has a recessed portion which is formed on the side of the photodiode 124and is linear in shape long along the direction approximatelyperpendicular to the optical axis of the on-chip lens 132.

To be more specific, the moth-eye section 125 is formed with a recessedportion having a curvature protruding toward the photodiode 124 whenviewing the cross section approximately parallel to the direction towardthe photodiode 124 from the light incident side in the semiconductorsubstrate 121. This recessed portion has a linear shape long along thedirection approximately perpendicular to the cross section approximatelyparallel to the direction toward the photodiode 124 from the lightincident side in the semiconductor substrate 121.

Therefore, in this example, the moth-eye section 125 has a shape inwhich, with one rectangular surface of the triangular prism directedtoward the photodiode 124, plural triangular prisms having approximatelythe same shape and approximately the same size are arranged in onedirection. That is, in the moth-eye section 125, plural recessedportions are arranged in the direction approximately perpendicular tothe length direction of the recessed portion linear in shape on theplane approximately perpendicular toward the photodiode 124 from thelight incident side.

Hence, the moth-eye section 125 has a saw-tooth shape when viewing thecross section approximately parallel to the direction toward thephotodiode 124 from the light incident side in the moth-eye section 125,to be more precise, the cross section approximately perpendicular to thelength direction of the recessed portion.

In this example, the portion indicated by arrow W41 is the recessedportion of the moth-eye section 125, for example, each recessed portionbeing indicated by hatching. Also, the portion indicated by arrow W42 isthe projected portion of the moth-eye section 125, for example.

Especially, with the moth-eye section 125, the recessed portion has acurvature and is roundly shaped. Therefore, in this example too, theuneven mold or peeling of the insulation film 128 or the color filter131 formed on the semiconductor substrate 121 can be prevented.

Sixth Embodiment <Yet Another Exemplary Configuration of Moth-EyeSection>

With reference to FIG. 8, the example was described in which themoth-eye section 125 has a normal pyramid structure in whichquadrangular pyramids approximately the same in shape and approximatelythe same in size are regularly arranged; however, it is also practicablethat each quadrangular pyramid is different in size from each other orarranged irregularly as illustrated in FIG. 10, for example. It shouldbe noted that with reference to FIG. 10, the same reference signs areassigned to the portions corresponding to those illustrated in FIG. 4,the description thereof being appropriately skipped.

In the example illustrated in FIG. 10, the upper side in the drawing ofthe semiconductor substrate 121 is the light incident side, namely, theside of the on-chip lens 132.

The moth-eye section 125 is formed on the surface of the light incidentside in the semiconductor substrate 121 and this moth-eye section 125has a normal pyramid structure in which quadrangular pyramid regionshaving apexes toward the upward side that is the side of the lightincident side, namely, the side of the on-chip lens 132 are irregularlyarranged. In addition, the size of each of the plural quadrangularpyramid regions is not equal to each other. That is, the size andarrangement of the quadrangular pyramids are random.

Especially, in the moth-eye section 125, the bottom side portions on theside of the photodiode 124 of each quadrangular pyramid region, theportions indicated by arrow W51 and arrow W52, for example, are recessedportions which have a curvature and are roundly shaped. This setupallows the prevention of the uneven mold or peeling of the insulationfilm 128 or the color filter 131 formed on the semiconductor substrate121.

In the above, the example in which, in a case where the moth-eye section125 has a normal pyramid structure, the size and arrangement of eachquadrangular pyramid region that is a recessed and projected portion ofthe moth-eye section 125 is random has been described; however, theshape of the conical region that is each recessed and projected portionmay also be random.

Likewise, the size, shape, and arrangement of each quadrangular pyramidregion may also be random in the inverted pyramid structure illustratedin FIG. 5, for example. That is, the moth-eye section 125 in whichplural pyramid regions including shapes and sizes different from eachother are irregularly arranged may be formed on the semiconductorsubstrate 121.

Seventh Embodiment <Still Another Exemplary Configuration of Pixel ArraySection>

In the example illustrated in FIG. 4, the insulation film 128 is formedonly between the surface of the moth-eye section 125 and the colorfilter 131; however, as illustrated in FIG. 11, the insulation film maybe formed also between pixels, namely, between the adjacent photodiodes124. It should be noted that with reference to FIG. 11, the samereference signs are assigned to the portions corresponding to thoseillustrated in FIG. 4, the description thereof being appropriatelyskipped.

In the example illustrated in FIG. 11, an insulation film 191 is formedon the portion between the upper surface in the drawing of the moth-eyesection 125 and the color filter 131 and the portion between adjacentphotodiodes 124, namely the boundary portion between pixels. Forexample, the insulation film 191 is constituted of the similar materialto the insulation film 128 illustrated in FIG. 4. Further, to be moreprecise, the portion between the insulation film 191 and each colorfilter 131 is formed with a planarization film not illustrated.

As described above, forming the insulation film 191 also between pixelsallows the insulation film 191 in this portion between pixels tofunction as an inter-pixel separation section for electricallyseparating pixels (photodiodes 124) from each other, thereby reducingthe noise in the photodiodes 124.

Eighth Embodiment <Yet Another Exemplary Configuration of Pixel ArraySection>

Further, in a case where the insulation film 191 is formed also on theportion between pixels as illustrated in FIG. 11, an inter-pixel lightblocking film may also be formed on the portion between pixels in theinsulation film 191, namely, the boundary portion between pixels asillustrated in FIG. 12. It should be noted that with reference to FIG.12, the same reference signs are assigned to the portions correspondingto those illustrated in FIG. 11, the description thereof beingappropriately skipped.

In the example illustrated in FIG. 12, not only the portion in the colorfilter 131 between pixels but also the portion between the adjacentphotodiodes 124 inside the insulation film 191 is formed with aninter-pixel light blocking film 211. That is, the portion of theinsulation film 191 is engraved to be formed with the inter-pixel lightblocking film 211. This setup enhances the light blocking performancebetween pixels further than the example illustrated in FIG. 11.

Here, the inter-pixel light blocking film 211 is constituted of tungsten(W), aluminum (Al), or copper (Cu), for example, as with the inter-pixellight blocking film 129 illustrated in FIG. 11. It should be noted thatthe material of the inter-pixel light blocking film 211 may be anymaterial that can block the light entered from the outside through theon-chip lens 132.

Ninth Embodiment <Different Exemplary Configuration of Pixel ArraySection>

Further, as illustrated in FIG. 13, a planarization film may be formedinstead of the insulation film 191 illustrated in FIG. 11 and areflection blocking film and a transparent insulation film may be formedbetween that planarization film and the surface of the semiconductorsubstrate 121. It should be noted that with reference to FIG. 13, thesame reference signs are assigned to the portions corresponding to thoseillustrated in FIG. 11, the description thereof being appropriatelyskipped.

In the example illustrated in FIG. 13, the portion between the upperside in the drawing of the moth-eye section 125 and the color filter 131and the portion between the adjacent photodiodes 124, namely, theboundary portion between pixels, are formed with a planarization film241. In this case, the portion between pixels of the planarization film241 also functions as an inter-pixel separation section as with the caseof the insulation film 191.

Further, the surface of the side of the semiconductor substrate 121 inthis planarization film 241 is formed with a transparent insulation film242 and the surface of the side of the semiconductor substrate 121 ofthis transparent insulation film 242 is formed with a reflectionblocking film 243.

Therefore, these transparent insulation film 242 and reflection blockingfilm 243 are formed on the surface portion of the side of the on-chiplens 132 of the moth-eye section 125 and the side surface portionadjacent to the portion providing the inter-pixel separation section ofthe planarization film 241 in the semiconductor substrate 121. Thissetup further enhances the light reflection blocking effects.

It should be noted that the planarization film 241 is formed with aninsulation film constituted of an organic material such as resin or aninsulation film constituted of silicon oxide (SiO₂). Further, thetransparent insulation film 242 and the reflection blocking film 243 areconstituted of the similar materials to those of the transparentinsulation film 162 and the reflection blocking film 161 described withreference to FIG. 7, for example. Still further, in the configurationillustrated in FIG. 13, an insulation film may be arranged between thesurface of the moth-eye section 125 and the reflection blocking film243.

Tenth Embodiment <Still Different Exemplary Configuration of Pixel ArraySection>

Further, as illustrated in FIG. 14, for example, in the configuration ofthe pixel array section 81 illustrated in FIG. 13, the inter-pixel lightblocking film 211 illustrated in FIG. 12 may be formed instead of theinter-pixel light blocking film 129. It should be noted that withreference to FIG. 14, the same reference signs are assigned to theportions corresponding to those illustrated in FIG. 12 or FIG. 13, thedescription thereof being appropriately skipped.

As with the case illustrated in FIG. 12, in the example illustrated inFIG. 14, not only the portion of the color filter 131 between pixels butalso the portion between the adjacent photodiodes 124 inside theplanarization film 241 is also formed with the inter-pixel lightblocking film 211.

Therefore, in this example, the reflection blocking film 243 and theinter-pixel light blocking film 211 can further enhance the lightblocking performance between pixels.

It should be noted that, in the embodiments described above, the casesin which the present technology is applied to CMOS image sensors and soon in which pixels for detecting signal charges corresponding to thelight quantity of visible light as physical quantity are arranged inmatrix have been described. However, the present technology is notlimited to the application to CMOS image sensors; namely, the presenttechnology is also applicable to entire solid-state image pickupdevices.

<Usage Examples of Solid-State Image Pickup Device>

FIG. 15 is a diagram illustrating an example of use in which thesolid-state image pickup device (image sensors) described above is used.

The solid-state image pickup device described above is usable in variouscases for sensing visible light, infrared light, ultraviolet light, Xray, and so on as follows, for example.

-   -   Apparatuses for taking images for viewing, such as digital        cameras, portable devices having camera functions, and so on;    -   Apparatuses for use in traffic, such as in-car sensors for        taking images of the front and rear directions, around and        inside automobiles, monitor cameras for monitoring running        automobiles and roads, and distance sensors for measuring the        distance between automobiles and so on, for the purpose of        safety driving such as automatic stop and the like and the        recognition of driver's states and the like;    -   Apparatuses for use in household appliances such as TVs,        refrigerators, air conditioners, and so on so as to take images        of user gestures and execute device control by following the        taken user gestures;    -   Apparatuses for use in medical and health care, such as        endoscopes, apparatuses for taking images of blood vessels by        photo-detecting infrared light, and so on;    -   Apparatuses for use in security, such as monitor cameras for use        in crime prevention, cameras for use in personal authentication,        and so on;    -   Apparatuses for use in beauty care, such as skin analyzers for        taking images of skin, microscopes for taking images of scalps,        and so on;    -   Apparatuses for use in sports, such as action cameras and        wearable cameras, and so on for sport uses; and    -   Apparatuses for use in agriculture, such as cameras for        monitoring farms and crop conditions.

Further, while the embodiments of the present technology have beendescribed using specific terms, such description is for illustrativepurpose only, and it is to be understood by those skilled in the artthat changes and variations may be made without departing from the gistof the present technology.

Further, the present technology can take the following configuration.

(1)

An image pickup device including:

a photoelectric conversion section that is arranged on a semiconductorsubstrate and configured to photoelectrically convert an incident light;

a moth-eye section that includes recesses and projections formed on asurface on a light incident side in the semiconductor substrate and has,when a cross section approximately parallel to a direction toward thephotoelectric conversion section from the light incident side is viewed,a recessed portion protruding toward the side of the photoelectricconversion section, the recessed portion having a curvature or apolygonal shape; and

a region that is arranged adjacent to and opposite to the photoelectricconversion section of the moth-eye section and has a refractive indexdifferent from a refractive index of the semiconductor substrate.

(2)

The image pickup device according to (1) above, in which a projectedportion protruding opposite to the photoelectric conversion section inthe moth-eye section has a curvature or a polygonal shape.

(3)

The image pickup device according to (2) above, in which the curvatureof the recessed portion is larger than the curvature of the projectedportion.

(4)

The image pickup device according to (2) above, in which the curvatureof the recessed portion is approximately equal to the curvature of theprojected portion.

(5)

The image pickup device according to any one of (1) through (4) above,in which the refractive index of the semiconductor substrate is largerthan the refractive index of the region.

(6)

The image pickup device according to any one of (1) through (5) above,in which the moth-eye section is formed with a plurality ofconical-shaped regions protruding toward the side of the photoelectricconversion section.

(7)

The image pickup device according to any one of (1) through (5) above,in which the moth-eye section is formed with a plurality ofconical-shaped regions protruding opposite to the photoelectricconversion section.

(8)

The image pickup device according to (6) or (7) above, in which theconical-shaped regions are arranged in lattice.

(9)

The image pickup device according to (6) or (7) above, in which theplurality of conical-shaped regions including sizes or shapes that aredifferent from each other are irregularly arranged.

(10)

The image pickup device according to any one of (1) through (5) above,in which the moth-eye section is formed with the plurality of therecessed portions that are linear in shape long along the directionapproximately perpendicular to the cross section and arranged side byside.

(11)

The image pickup device according to any one of (1) through (10) above,in which, between the photoelectric conversion sections mutuallyadjacent to each other in the semiconductor substrate, an inter-pixelseparation section configured to electrically separate the photoelectricconversion sections from each other is arranged.

(12)

The image pickup device according to (11) above, in which an inter-pixellight blocking film for blocking the light is formed inside theinter-pixel separation section.

(13)

An electronic apparatus including:

a photoelectric conversion section that is arranged on a semiconductorsubstrate and configured to photoelectrically convert an incident light;

a moth-eye section that includes recesses and projections formed on asurface on a light incident side in the semiconductor substrate and has,when a cross section approximately parallel to a direction toward thephotoelectric conversion section from the light incident side is viewed,a recessed portion protruding toward the side of the photoelectricconversion section, the recessed portion having a curvature or apolygonal shape; and

a region that is arranged adjacent to and opposite to the photoelectricconversion section of the moth-eye section and has a refractive indexdifferent from a refractive index of the semiconductor substrate.

REFERENCE SIGNS LIST

-   41 . . . Image pickup apparatus, 52 . . . Solid-state image pickup    device, 81 . . . Pixel array section, 121 . . . Semiconductor    substrate, 124 . . . Photodiode, 125 . . . Moth-eye section, 129 . .    . Inter-pixel light blocking film, 131 . . . Color filter, 132 . . .    On-chip lens, 161 . . . Reflection blocking film, 162 . . .    Transparent insulation film, 191 . . . Insulation film, 211 . . .    Inter-pixel light blocking film, 242 . . . Transparent insulation    film, 243 . . . Reflection blocking film

What is claimed is:
 1. An image pickup device comprising: aphotoelectric conversion section that is arranged on a semiconductorsubstrate and configured to photoelectrically convert an incident light;a moth-eye section that includes recesses and projections formed on asurface on a light incident side in the semiconductor substrate and has,when a cross section approximately parallel to a direction toward thephotoelectric conversion section from the light incident side is viewed,a recessed portion protruding toward the side of the photoelectricconversion section, the recessed portion having a curvature or apolygonal shape; and a region that is arranged adjacent to and oppositeto the photoelectric conversion section of the moth-eye section and hasa refractive index different from a refractive index of thesemiconductor substrate.
 2. The image pickup device according to claim1, wherein a projected portion protruding opposite to the photoelectricconversion section in the moth-eye section has a curvature or apolygonal shape.
 3. The image pickup device according to claim 2,wherein the curvature of the recessed portion is larger than thecurvature of the projected portion.
 4. The image pickup device accordingto claim 2, wherein the curvature of the recessed portion isapproximately equal to the curvature of the projected portion.
 5. Theimage pickup device according to claim 1, wherein the refractive indexof the semiconductor substrate is larger than the refractive index ofthe region.
 6. The image pickup device according to claim 1, wherein themoth-eye section is formed with a plurality of conical-shaped regionsprotruding toward the side of the photoelectric conversion section. 7.The image pickup device according to claim 1, wherein the moth-eyesection is formed with a plurality of conical-shaped regions protrudingopposite to the photoelectric conversion section.
 8. The image pickupdevice according to claim 6, wherein the conical-shaped regions arearranged in lattice.
 9. The image pickup device according to claim 6,wherein the plurality of conical-shaped regions including sizes orshapes that are different from each other are irregularly arranged. 10.The image pickup device according to claim 1, wherein the moth-eyesection is formed with the plurality of the recessed portions that arelinear in shape long along the direction approximately perpendicular tothe cross section and arranged side by side.
 11. The image pickup deviceaccording to claim 1, wherein, between the photoelectric conversionsections mutually adjacent to each other in the semiconductor substrate,an inter-pixel separation section configured to electrically separatethe photoelectric conversion sections from each other is arranged. 12.The image pickup device according to claim 11, wherein an inter-pixellight blocking film for blocking the light is formed inside theinter-pixel separation section.
 13. An electronic apparatus comprising:a photoelectric conversion section that is arranged on a semiconductorsubstrate and configured to photoelectrically convert an incident light;a moth-eye section that includes recesses and projections formed on asurface on a light incident side in the semiconductor substrate and has,when a cross section approximately parallel to a direction toward thephotoelectric conversion section from the light incident side is viewed,a recessed portion protruding toward the side of the photoelectricconversion section, the recessed portion having a curvature or apolygonal shape; and a region that is arranged adjacent to and oppositeto the photoelectric conversion section of the moth-eye section and hasa refractive index different from a refractive index of thesemiconductor substrate.